1. Field of the Invention
The invention pertains to a tree fastener with wings which are split along the tool parting line and offset half of the branch spacing distance.
2. Description of the Prior Art
Tree fasteners with radially extending branches or wings for insertion into apertures in sheet metal and similar structures are known in the prior art. However, prior art tree fastener designs have a minimum branch spacing dictated by tooling constraints. The branch spacing governs the amount of play when the fastener is installed. If the panel thickness is such that one set of branches is unable to clear the panel, then the tree fastener is retained by the next lower set of branches. This creates play and rattles which are unacceptable in motor vehicles and similar applications. Ideally, the branches would always be located to clear the panels precisely, but thickness variations, burrs and manufacturing tolerances prevent the ideal situation. Some prior art designs rely on flexible arms to compensate for this play and these intolerances, but many times design constraints prevent the use of flexible arms.
Examples of prior art tree fasteners are disclosed in U.S. Pat. No. 5,468,108 entitled "Spiral Flex Tree Fastener" issued on Nov. 21, 1995 to Sullivan et al.; U.S. Pat. No. 5,039,267 entitled "Tee Tree Fastener" issued on Aug. 13, 1991 to Wollar; U.S. Pat. No. 4,776,739 entitled "Plastic Drive Fastener" issued on Oct. 11, 1988 to Hamman; U.S. Pat. No. 4,728,238 entitled "Plastic Drive Fastener" issued on Mar. 1, 1988 to Chisholm et al.; U.S. Pat. No. 4,402,641 entitled "Self Centering Fastener" issued on Sep. 6, 1983 to Arff; and U.S. Pat. No. 4,392,278 entitled "Fastener" issued on Jul. 12, 1983 to Mugglestone.